This application claims the priority benefit of Taiwan application serial No. 89118679, filed Sep. 13, 2000.
1. Field of the Invention
The invention relates in general to a structure and a fabrication method of a flat panel display comprising address lines. More particularly, this invention relates to a structure and a fabrication method of a flat panel display comprising address lines having mending layers.
2. Description of the Related Art
In the operation of a flat panel display, two orthogonal address lines, namely, scan lines and data lines, are used to control the pixels arranged in a matrix for image display. The scan lines and the data lines are perpendicular to each other. Each intersection of the scan lines and the data lines is located near by a pixel. During the operation of the flat panel display, each scan line is driven sequentially, and the status of each corresponding pixel, that is, the image shown on the flat panel display, is changed according to the transmission signal from each data line.
The scan lines and data lines have to be long enough to cross the whole display area of the flat panel display device. Due to certain amount of inevitable defects or contamination, defective scan lines or data lines are often found on the substrate. As a consequence, pixels connected to those defective lines could not receive data signal sand display properly. Accordingly, some mending methods are proposed.
For example, when one of the data lines is broken, a metal line deposited around the display area is welded and electrically connected with the two terminals of the broken data line. Accordingly, all pixels along the broken data line receive data signal at the same time from both terminals. However, this method might induce higer stray capacitance and resistance. As a result, pixels connected with the broken data line would abnormally operate. That is, the overall image quality of the flat panel display is degraded. In addition, if a defect happens to a scan line and mended by the above-mentioned method, high stray capacitance would also cause a serious RC delay for the scan line. The RC delay would distort scan voltage waveform along the scan line result in a weak line.
The present invention provides a method of fabricating an address line having a mending layer on a flat panel display. A substrate is provided. A first address line and a first mending layer are formed on the substrate. The first mending layer is electrically insulated from the first address line. The first mending layer is partitioned into different segments by the first address line. A first insulating layer is formed over the substrate to cover at least the first address line and the first mending layer. A second address line is formed on the first insulating layer over the first mending layer and crosses the first address line. A second insulating layer is formed over the substrate to cover at least the second address line. A second mending layer is formed on the second insulating layer over the second address line and crosses the first address line. Preferably, a coverage of the second mending layer is partly overlapped with the first mending layer at two sides of the first address line. Besides, it is preferable that the material for forming the first address line and the first mending layer is the same, and the first address line and the first mending layer are formed simultaneously.
In the above method, a third mending layer can further be formed over the first address line while forming the second address line. The third mending layer is electrically insulated from the second address line.
The present invention further provides a structure of an address line having a mending layer on a flat panel display. The structure comprises a first address line, a first mending layer, a first insulating layer, a second address line, a second insulating layer and a second mending layer. The first address line and the first mending layer are electrically insulated from each other and formed on an insulating substrate. The first mending layer is partitioned into different segments by the first address line. The first insulating layer covers at least the first address line and the first mending layer. The second address line is located on the first insulating layer over the mending layer and crosses the first address line. The second insulating layer covers at least the second address line. The second mending layer is located on the second insulating layer over the second address line and crosses the first address line.
The above structure further comprises a third mending layer located on the first insulating layer over the first address line and electrically insulated from the second address line.
In addition, in the above method and structure, the first address line includes a scan line and the second address line includes a data line. It is preferable that the second mending layer is made of a material similar to that of the pixel on the flat panel display. The second mending layer can be formed simultaneously with the pixel to simplify the fabrication process.
The address line having a mending layer can solve the problem of broken line on a flat panel display. As mentioned above, the first mending layer is formed under the data line in a flat panel display. When a defective point happens to the data line, the first mending layer located below the defective point is laserwelded and connected electrically with the data line. The data line is thus mended with the first mending layer. In specific case, when the defective point is located on the intersection portion of the data line over the scan line, the second mending layer is welded and electrically connected with two ends of the data line. Therefore, with the coverage of the second mending layer partly overlapping the coverage of the first mending layer on both sides of the first address line, no matter where the defective point is located on the data line, it can be easily repaired.
In addition, the third mending layer can be further formed over the scan line. Therefore, when a defective point happens to the scan line, the third mending layer can be welded and electrically connected with the broken scan line.
The first mending layer can be used to mend the broken data line thereon, the second mending layer is used to mend the broken part of the data line located at an intersection between the data line and the scan line, and the third mending layer is used to mend the underlying broken scan line. Therefore, without external bonding or wiring, the broken address lines (the data line and the scan line) can be mended to ensure a normal operation of every single pixel. The yield is thus greatly improved.
Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.